1. Field
Apparatuses consistent with exemplary embodiments relate generally to a glass apparatus. More particularly, exemplary embodiments relate to a glass apparatus for watching a polarized image by effectively blocking flicker and crosstalk by compensating for a phase difference of the polarized birefringent image.
2. Description of the Related Art
Stereoscopic display technology is applied to various fields such as information communication, broadcasting, medical care, educational training, military, game, animation, virtual space, computer-aided design (CAD), and industrial technology, and is the core technology of next-generation 3D stereoscopic multimedia information communications, which is commonly required in those various fields.
In general, humans perceive relative depths complexly based on thickness change of eye lenses according to a location of an object to observe, an angle difference between both eyes and the object, location and shape differences of the object perceived by two eyes, parallax according to movement of the object, psychology, and memory effects.
Among the factors above, binocular disparity resulting from the horizontal separation of about 6-7 cm between two eyes of the human, is the most important factor in the stereoscopy. That is, the human sees the object with the angle difference because of the binocular disparity, the images input to the eyes have different images, and these two images are input to the brain through the retinas. The brain can create the original 3D stereoscopic vision by accurately uniting the two information.
Stereoscopic image display devices are categorized into a glass type using special glasses and a non-glass type without using special glasses. The glass type includes a color filter scheme which separates and selects the image using complementary color filters, a polarized filter scheme which separates left-eye and right-eye images by restricting the light using a combination of orthogonal polarizing elements, and a shutter glass scheme which creates illusion of the 3D image by alternately closing the left eye and the right eye in correspondence with a synchronization signal projecting a left-eye image signal and a right-eye image signal on a screen.
The polarized filter scheme alternately displays left-eye image data and right-eye image data on the horizontal line basis in a display panel and switches a polarization property incoming to polarizing glasses through a patterned retarder. Accordingly, the 3D image can be represented by spatially dividing the left-eye image and the right-eye image.
The polarized filter scheme features low crosstalk of the left eye and the right eye and high luminance in the 3D image. However, since the left-eye image and the right-eye image are spatially separated and displayed, the vertical resolution of the left-eye and right-eye images is halved in comparison with the physical vertical resolution of the panel.
The polarized filter scheme can be applied to not only the 3D image but also a multi-view environment where a plurality of viewers can watch different contents. In this case, a display device can represent a multi-view image by spatially separating the left-eye image and the right-eye image in the similar manner. Users watch different images through glass apparatuses corresponding to polarization directions of the multi-view image and having different polarization directions.
By contrast, according to the shutter glass scheme, the display device represents the 3D image by alternately displaying the left-eye image and the right-eye image on the frame basis, and opening and closing left-eye and right-eye shutters of the shutter glasses in synchronization with the display timing. The shutter glasses opens only the left-eye shutter during odd frames displaying the left-eye image, opens only the right-eye shutter during even frames displaying the right-eye image, and thus produces the binocular disparity based on the time division.
The shutter glass scheme can be applied to not only the 3D image but also the multi-view environment where the plurality of the viewers can watch different contents. In this case, the display device alternately displays one content and other contents, and opens and closes the left-eye and right-eye shutters of the shutter glasses in synchronization with the display timing so that the user wearing one glasses can watch only the corresponding content. Thus, several users can watch different contents.
The shutter glass scheme generally uses a liquid crystal shutter. The liquid crystal shutter opens or closes the shutters by changing orientation of the liquid crystal by applying an electrode to the liquid crystal.
The liquid crystal shutter glasses do not degrade the vertical resolution of the left-eye and right-eye images in the 3D image, but are subject to the low luminance of the 3D image because of the short data-on time of the liquid crystal shutter glasses and the 3D crosstalk according to synchronization of the display device and the liquid crystal shutter glasses and on-off switch response characteristics.
Preferably, the shutter glass scheme and the polarized filter scheme can be used together. In this case, the display device can alternately arrange and display the frames of the polarized left-eye image and right-eye image. The shutter on/off timing of the glasses is synchronized with the image frames alternately displayed by the display device. The glasses include a polarizer for passing the polarized image.
When the shutter glass scheme and the polarized filter scheme are used together, several users can watch different 3D contents. For example, one user can watch the horizontally polarized 3D content and another user can watch the vertically polarized 3D content at the same time. In this case, the glasses of each user include the polarizer having an orthogonal polarization axis.
In this example, the flicker is observed due to the difference of the lighting around the glasses and the shutter frequency, and a method for removing the flicker is required.
Also, when the user wearing the liquid crystal shutter glasses leans his/her neck, the glasses are tilted at a certain angle based on the horizontal plane. In this case, even when the glasses are closed, the crosstalk passes the image. Hence, it is necessary to prevent the crosstalk.